Custom fields and merge tags
Store anything about a contact, then print it in an email.
Beyond name, email and phone you can store anything you like on a contact — company, plan, renewal date, city. Define them once in Attributes, then print them in an email with a merge tag.
Creating a field
Give it a key like COMPANY or RENEWAL_DATE. The key is what you type in an email, so keep it short and memorable. Fields are shared across your whole account — every contact can have a value for any of them.
Fill them by importing a CSV column, editing a contact, collecting them on a signup form, setting one inside an automation, or through the API.
Printing them in an email
Wrap the name in double braces. The built-in ones:
{{firstName}},{{lastName}},{{name}}{{email}}
Your own fields use their key: {{COMPANY}}. Tags work in the subject line and the preheader as well as the body, and each recipient gets their own value substituted at send time.
What happens when the value is blank
An empty value prints nothing, silently
“Hi {{firstName}},” to someone with no first name sends “Hi ,” — and a misspelled tag does the same thing, because a tag we don’t recognise is replaced with nothing rather than left on the page.
It fails quietly in both directions, which is exactly why it’s worth testing deliberately.
Two habits that avoid it:
- Write copy that survives a blank. “Hi there” beats “Hi <name>” when a tenth of your list has no first name.
- Find the gaps first. Build a segment with “first name is not set” and you’ll know how many people it affects before you send.
Common issues
The tag printed nothing
Either that contact has no value, or the key doesn’t match. Check the exact key in Attributes — matching is exact, so Company and COMPANY are different tags.
The tag printed literally in the email
Usually a stray space or a smart quote inside the braces, often from pasting out of a word processor. Retype it.
Penny used a tag I don't have
It can’t — AI output is checked against your real field keys before you see it, precisely because a hallucinated tag would render as a hole in thousands of inboxes.
FAQs
Can I set a fallback for a blank value?+
Not inside the tag. Write copy that reads well without it, or send a different version to the people who are missing it — a segment on “is not set” makes that easy.
Do merge tags work in the subject line?+
Yes, and they measurably help — but the blank problem is more visible there, since a subject beginning “, your order” is what lands in the inbox list.
Is there a limit to how many fields I can have?+
No practical limit. Do keep the keys tidy: they appear in the import mapping screen and in every export, so a hundred half-used fields makes both harder to read.